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  <div class="section" id="scaling-instances">
<span id="id1"></span><h1>Scaling Instances<a class="headerlink" href="#scaling-instances" title="Permalink to this headline">🔗</a></h1>
<p>You can scale CDAP components (instances of services and workers) using:</p>
<ul class="simple">
<li>the <span class="xref std std-ref">Scaling</span> methods of the
<span class="xref std std-ref">Lifecycle HTTP RESTful API</span>;</li>
<li>the <span class="xref std std-ref">Get/Set Commands</span> of the
<span class="xref std std-ref">Command Line Interface</span>; or</li>
<li>the <span class="xref std std-ref">ProgramClient API</span> of the
<span class="xref std std-ref">Java Client API</span>.</li>
</ul>
<p>The examples given below use the <span class="xref std std-ref">Lifecycle HTTP RESTful API</span>.</p>
<div class="section" id="scaling-flowlets">
<h2>Scaling Flowlets<a class="headerlink" href="#scaling-flowlets" title="Permalink to this headline">🔗</a></h2>
<p>You can query and set the number of instances executing a given flowlet
by using the <code class="docutils literal notranslate"><span class="pre">instances</span></code> parameter with HTTP GET and PUT methods:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">GET</span> <span class="o">/</span><span class="n">v3</span><span class="o">/</span><span class="n">namespaces</span><span class="o">/&lt;</span><span class="n">namespace</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">apps</span><span class="o">/&lt;</span><span class="n">app</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">flows</span><span class="o">/&lt;</span><span class="n">flow</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">flowlets</span><span class="o">/&lt;</span><span class="n">flowlet</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">instances</span>
<span class="n">PUT</span> <span class="o">/</span><span class="n">v3</span><span class="o">/</span><span class="n">namespaces</span><span class="o">/&lt;</span><span class="n">namespace</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">apps</span><span class="o">/&lt;</span><span class="n">app</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">flows</span><span class="o">/&lt;</span><span class="n">flow</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">flowlets</span><span class="o">/&lt;</span><span class="n">flowlet</span><span class="o">-</span><span class="n">id</span><span class="o">&gt;/</span><span class="n">instances</span>
</pre></div>
</div>
<p>with the arguments as a JSON string in the body:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="p">{</span> <span class="s">&quot;instances&quot;</span> <span class="p">:</span> <span class="o">&lt;</span><span class="n">quantity</span><span class="o">&gt;</span> <span class="p">}</span>
</pre></div>
</div>
<table border="1" class="docutils">
<colgroup>
<col width="20%" />
<col width="80%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Parameter</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">namespace-id</span></code></td>
<td>Namespace ID</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">app-id</span></code></td>
<td>Name of the application being called</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">flow-id</span></code></td>
<td>Name of the flow</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">flowlet-id</span></code></td>
<td>Name of the flowlet</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">quantity</span></code></td>
<td>Number of instances to be used</td>
</tr>
</tbody>
</table>
<p class="rubric">Examples</p>
<ul>
<li><p class="first">Retrieve the number of instances of the flowlet <em>saver</em> in the flow <em>WhoFlow</em> of the
application <em>HelloWorld</em> in the namespace <em>default</em>:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">GET</span> <span class="o">/</span><span class="n">v3</span><span class="o">/</span><span class="n">namespaces</span><span class="o">/</span><span class="k">default</span><span class="o">/</span><span class="n">apps</span><span class="o">/</span><span class="n">HelloWorld</span><span class="o">/</span><span class="n">flows</span><span class="o">/</span><span class="n">WhoFlow</span><span class="o">/</span><span class="n">flowlets</span><span class="o">/</span><span class="n">saver</span><span class="o">/</span><span class="n">instances</span>
</pre></div>
</div>
</li>
<li><p class="first">Set the number of instances of the flowlet <em>saver</em> in the flow <em>WhoFlow</em> of the
application <em>HelloWorld</em> in the namespace <em>default</em>:</p>
<div class="highlight-java notranslate"><div class="highlight"><pre><span></span><span class="n">PUT</span> <span class="o">/</span><span class="n">v3</span><span class="o">/</span><span class="n">namespaces</span><span class="o">/</span><span class="k">default</span><span class="o">/</span><span class="n">apps</span><span class="o">/</span><span class="n">HelloWorld</span><span class="o">/</span><span class="n">flows</span><span class="o">/</span><span class="n">WhoFlow</span><span class="o">/</span><span class="n">flowlets</span><span class="o">/</span><span class="n">saver</span><span class="o">/</span><span class="n">instances</span>
</pre></div>
</div>
<p>with the arguments as a JSON string in the body:</p>
<div class="highlight-json-ellipsis notranslate"><div class="highlight"><pre><span></span><span class="p">{</span> <span class="nt">&quot;instances&quot;</span> <span class="p">:</span> <span class="mi">2</span> <span class="p">}</span>
</pre></div>
</div>
</li>
</ul>
</div>
<div class="section" id="scaling-services">
<h2>Scaling Services<a class="headerlink" href="#scaling-services" title="Permalink to this headline">🔗</a></h2>
<p>You can query or change the number of instances of a service
by using the <code class="docutils literal notranslate"><span class="pre">instances</span></code> parameter with HTTP GET or PUT methods:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">GET /v3/namespaces/&lt;namespace-id&gt;/apps/&lt;app-id&gt;/services/&lt;service-id&gt;/instances</span>
<span class="go">PUT /v3/namespaces/&lt;namespace-id&gt;/apps/&lt;app-id&gt;/services/&lt;service-id&gt;/instances</span>
</pre></div>
</div>
<p>with the arguments as a JSON string in the body:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">{ &quot;instances&quot; : &lt;quantity&gt; }</span>
</pre></div>
</div>
<table border="1" class="docutils">
<colgroup>
<col width="20%" />
<col width="80%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Parameter</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">namespace-id</span></code></td>
<td>Namespace ID</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">app-id</span></code></td>
<td>Name of the application</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">service-id</span></code></td>
<td>Name of the service</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">quantity</span></code></td>
<td>Number of instances to be used</td>
</tr>
</tbody>
</table>
<p><strong>Note:</strong> You can scale system services using the Monitor HTTP RESTful API
<span class="xref std std-ref">Scaling System Services</span>.</p>
<p class="rubric">Examples</p>
<ul>
<li><p class="first">Retrieve the number of instances of the service <em>CatalogLookup</em> in the application
<em>PurchaseHistory</em> in the namespace <em>default</em>:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">GET /v3/namespaces/default/apps/PurchaseHistory/services/CatalogLookup/instances</span>
</pre></div>
</div>
</li>
<li><p class="first">Set the number of handler instances of the service <em>RetrieveCounts</em>
of the application <em>WordCount</em>:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">PUT /v3/namespaces/default/apps/WordCount/services/RetrieveCounts/instances</span>
</pre></div>
</div>
<p>with the arguments as a JSON string in the body:</p>
<div class="highlight-json-ellipsis notranslate"><div class="highlight"><pre><span></span><span class="p">{</span> <span class="nt">&quot;instances&quot;</span> <span class="p">:</span> <span class="mi">2</span> <span class="p">}</span>
</pre></div>
</div>
</li>
<li><p class="first">Using <code class="docutils literal notranslate"><span class="pre">curl</span></code> and the <a class="reference external" href="../../../developer-manual/getting-started/sandbox/index.html#sandbox-index" title="(in Cask Data Application Platform v6.1.1)"><span class="xref std std-ref">CDAP Sandbox</span></a>:</p>

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<div class="tab-pane tab-pane-linux active">
<div class="code code-tab">
<div class="highlight-console">
<!-- tabbed-parsed-literal start -->
<div class="highlight"><pre><span></span><span class="gp">$</span> curl -w<span class="s2">&quot;\n&quot;</span> -X PUT <span class="s2">&quot;http://localhost:11015/v3/namespaces/default/apps/WordCount/services/RetrieveCounts/instances&quot;</span> <span class="se">\</span>
  -d <span class="s1">&#39;{ &quot;instances&quot; : 2 }&#39;</span></span>
</pre></div>
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</div>
</div>
<div class="tab-pane tab-pane-windows ">
<div class="code code-tab">
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<!-- tabbed-parsed-literal start -->
<div class="highlight"><pre><span></span><span class="gp">&gt;</span> curl -X PUT <span class="s2">&quot;http://localhost:11015/v3/namespaces/default/apps/WordCount/services/RetrieveCounts/instances&quot;</span> ^
<span class="go">  -d &quot;{ \&quot;instances\&quot; : 2 }&quot;</span>
</pre></div>
<!-- tabbed-parsed-literal end --></div>
</div>
</div>
</div>
</div>
</li>
</ul>
</div>
<div class="section" id="scaling-workers">
<h2>Scaling Workers<a class="headerlink" href="#scaling-workers" title="Permalink to this headline">🔗</a></h2>
<p>You can query or change the number of instances of a worker by using the <code class="docutils literal notranslate"><span class="pre">instances</span></code>
parameter with HTTP GET or PUT methods:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">GET /v3/namespaces/&lt;namespace-id&gt;/apps/&lt;app-id&gt;/workers/&lt;worker-id&gt;/instances</span>
<span class="go">PUT /v3/namespaces/&lt;namespace-id&gt;/apps/&lt;app-id&gt;/workers/&lt;worker-id&gt;/instances</span>
</pre></div>
</div>
<p>with the arguments as a JSON string in the body:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">{ &quot;instances&quot; : &lt;quantity&gt; }</span>
</pre></div>
</div>
<table border="1" class="docutils">
<colgroup>
<col width="20%" />
<col width="80%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">Parameter</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">namespace-id</span></code></td>
<td>Namespace ID</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">app-id</span></code></td>
<td>Name of the application</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">worker-id</span></code></td>
<td>Name of the worker</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">quantity</span></code></td>
<td>Number of instances to be used</td>
</tr>
</tbody>
</table>
<p class="rubric">Example</p>
<p>Retrieve the number of instances of the worker <em>DataWorker</em> in the application
<em>DemoApp</em> in the namespace <em>default</em>:</p>
<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="go">GET /v3/namespaces/default/apps/DemoApp/workers/DataWorker/instances</span>
</pre></div>
</div>
</div>
</div>

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